A method to reduce false targets during active laser detection of electro-optical targets

Abstract

This invention discloses a method for reducing false targets during active laser detection and electro-optical targeting. It extracts target positions by controlling the laser illumination on and off, and using the frame difference between adjacent frames with and without laser illumination, through a threshold. Simultaneously, it lowers the threshold by a certain percentage to extract targets again. If the targets extracted using the original threshold include some false targets, the area and shape of these false targets will change due to the threshold reduction. By judging the target area and shape, false targets from the original threshold extraction are then eliminated. This invention can extract targets by combining the area and shape of the electro-optical target with a set threshold. It is simple to design, easy to implement, and has wide applicability.

Description

Technical Field

[0001] This invention relates to photoelectric tracking, and more specifically to a method for reducing false targets during active laser detection of photoelectric targets. Background Technology

[0002] When laser illumination is active, targets are detected through the "cat's eye effect" generated by electro-optical targeting, thus identifying potential threats in advance. The echo intensity generated by electro-optical targeting is much greater than the diffuse reflection intensity of false targets in the environment. Therefore, by utilizing the frame difference between laser illumination and non-illumination, targets can be extracted by setting a threshold. This method is simple to implement, has low latency, and is widely applicable. However, in complex environments, when extracting targets using a single threshold, objects such as window ridges, car headlights, metallic reflective signs, and some highly reflective objects may be misidentified as electro-optical targeting systems, resulting in a large number of false targets. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for reducing false targets during active laser detection and photoelectric aiming. This method can extract false targets in the target by combining the area and shape of the photoelectric aiming with a set threshold.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for reducing false targets during active laser detection and photoelectric aiming. By controlling the laser illumination to be on and off, the target position is extracted by using a threshold based on the frame difference between two adjacent frames when the laser is illuminating and not illuminating. At the same time, the target is extracted again by lowering the threshold by a certain percentage based on the original threshold. Since the aperture and area of ​​a typical photoelectric aiming system are fixed, if the target extracted by the original threshold contains some false targets, the area and shape of the false targets will change by lowering the threshold. Then, by judging the target area and shape, the false targets in the target extracted by the original threshold are eliminated.

[0005] The specific operating steps of this invention are as follows:

[0006] S1. By controlling the laser's on / off state between two adjacent frames, we can obtain images of laser illumination and images of non-illumination. The frame difference is compared to a threshold m to extract targets larger than m. Their area and shape are calculated, and invalid targets are then removed based on area and shape criteria, resulting in a target set (m). 1， m 2， m 3…. m n );

[0007] S2. In step S1, the two frames of images are simultaneously compared against a threshold ψ*m. Targets larger than ψ*m are extracted, and their values ​​are (n...). 1， n 2， n 3…. n n), ψ takes the value [0,1];

[0008] S3. Transfer the target set (m) obtained in step S1 to... 1， m 2， m 3…. m n Map one-to-one to the target set (n) obtained in step S2 1， n 2， n 3…. n n ), remove the target set (n) 1， n 2， n 3…. n n The target set (m) is not included. 1， m 2， m 3…. m n The goal is to obtain a new target set (p) in step S2. 1， p 2， p 3…. p n );

[0009] S4. Calculate the target set (p) in step S3. 1， p 2， p 3…. p n The area and shape of each target in the set are determined, and targets that do not meet the conditions are mapped to the target set (m) in step S1 based on the area and shape criteria. 1， m 2， m 3…. m n The targets in the target set (q) are removed, resulting in a new target set (q) in step S1. 1， q 2， q 3…. q n );

[0010] S5. The target set (q) in step S4 1， q 2， q 3…. q n This is the valid target of the final output.

[0011] The present invention provides a method for reducing false targets during active laser detection and photoelectric aiming, which has the following advantages: Targets can be extracted by considering the area and shape of the photoelectric target and setting a threshold. Compared to a single threshold extraction method, this method reduces false targets. Compared to methods that extract targets using multiple thresholds, the second threshold in this method is designed by lowering the threshold based on the original threshold. The threshold only needs to be set once, and the target extracted by the second threshold must include the target extracted by the first threshold. Furthermore, target extraction using the original threshold and target extraction using the lower threshold can be performed simultaneously, resulting in low system latency. The invention is simple to design, easy to implement, and has wide applicability. Attached Figure Description

[0012] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0013] The following description, in conjunction with the accompanying drawings, details a method for reducing false targets during laser active detection and optoelectronic aiming according to the present invention.

[0014] This invention provides a method for reducing false targets during active laser detection and electro-optical aiming, see [link to relevant documentation]. Figure 1 ,

[0015] Take two adjacent frames, such as frame (n-1) and frame n (n≥2). The laser is on in frame (n-1) and off in frame n. Compare the frame difference between the two frames to the set threshold m and the reduced threshold ψ*m, where ψ takes values ​​[0,1]. Binarize the images by setting pixel values ​​greater than the threshold to 1 and pixel values ​​less than the threshold to 0, reducing the amount of subsequent data and computation. Perform morphological filtering on the binarized images. Extract the location, area, and shape of the targets from the filtered images through connected components, resulting in two target sets containing target information: target set A generated by threshold m and target set B generated by threshold ψ*m. If the number of targets in target set A is zero, output it directly. Otherwise, perform area and shape discrimination on each target in target set A, discard targets that do not meet the conditions, and determine if the number of targets in target set A is zero. If it is zero, output it directly; otherwise, obtain a new target set P. The target set P is compared with the target set B. Each target in target set P is mapped to target set B. The mapped targets in target set B are then judged by area and shape. If a target does not meet the judgment criteria, the corresponding target in target set P is removed. After traversing target set P, a new target set Q is obtained from target set P. Target set Q is the output of valid targets.

Claims

1. A method for reducing false targets during active laser detection and photoelectric aiming, characterized in that: By controlling the laser illumination on and off, the target position is extracted by thresholding the frame difference between two adjacent frames when the laser is on and off. Simultaneously, the target is extracted again by lowering the threshold by a certain percentage. Since the aperture and area of ​​a typical optoelectronic observation system are fixed, if the target extracted by the original threshold includes some false targets, the area and shape of the false targets will change by lowering the threshold. Therefore, by judging the target area and shape, the false targets extracted by the original threshold are eliminated. The specific operation steps are as follows: S1. By controlling the laser's on / off state between two adjacent frames, we can obtain images of the laser-illuminated and unilluminated frames. The frame difference is compared to a threshold m. Targets larger than m are extracted, their area and shape are calculated, and invalid targets are removed based on area and shape criteria, resulting in a target set (m). 1， m 2， m 3，…， m h ); S2. In step S1, the two frames of images are synchronously compared with a threshold ψ*m. Targets larger than ψ*m are extracted, and these targets are (n... 1， n 2， n 3，…， n i ), ψ takes the value [0,1]; S3. Transfer the target set (m) obtained in step S1 to... 1， m 2， m 3，…， m h Map one-to-one to the target set (n) obtained in step S2 1， n 2， n 3，…， n i ), remove the target set (n) 1， n 2， n 3，…， n i The target set (m) is not included. 1， m 2， m 3，…， m h The goal is to obtain a new target set (p). 1， p 2， p 3，…， p j ); S4. Calculate the target set (p) obtained in step S3. 1， p 2， p 3，…， p j The area and shape of each target in the set are determined, and targets that do not meet the conditions are mapped to the target set (m) obtained in step S1 based on the area and shape criteria. 1， m 2， m 3，…， m h The targets in q are removed to obtain a new target set. 1， q 2， q 3,…, q k ); S5. Target set (q) in step S4 1， q 2， q 3,…, q k This is the valid target of the final output.

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